Projectile fragmentation of ${}^{40}\mathrm{Ca}$, ${}^{48}\mathrm{Ca}$, ${}^{58}\mathrm{Ni}$, and ${}^{64}\mathrm{Ni}$ at 140 MeV/nucleon

We have measured fragment cross-sections of projectile fragmentation reactions using primary beams of ${}^{40}\mathrm{Ca}$, ${}^{48}\mathrm{Ca}$, ${}^{58}\mathrm{Ni}$, and ${}^{64}\mathrm{Ni}$ at 140 MeV/nucleon on ${}^9\mathrm{Be}$ and ${}^{181}\mathrm{Ta}$ targets. The cross-sections were obtained by integrating the momentum distributions of isotopes with $Z⩾5$ measured in the A1900 fragment separator. We compare the extracted cross-sections to the predictions of the empirical parametrization of fragmentation cross-sections (EPAX).

Figure 1

The A1900 fragment separator in stand-alone mode. Beam intensity monitors [NaI(Tl) and BaF${}_2$] were located at the target station (TA). The momentum slit at the intermediate image (I2) defined the momentum opening (0.2% in d$p/p$). The detector setup at the focal plane (FP) was used to identify fragments. The first dipole (out of four) is labeled D1 and the second quadrupole triplet (out of eight) is labeled as Q2.

Figure 2

Raw (left panel) and calibrated (right panel) particle identification spectrum for ${}^{48}\mathrm{Ca}$+${}^9\mathrm{Be}$ reactions at $B\rho =3.2$ Tm.

Figure 3

Dependence of the transmission correction, ɛ, on the fragment mass number, $A$, for ${}^{48}\mathrm{Ca}$+${}^9\mathrm{Be}$ reactions.

Figure 4

Momentum distributions for ${}^{33}\mathrm{P}$ produced in fragmentation of ${}^{40}\mathrm{Ca}$ (left panel) and ${}^{48}\mathrm{Ca}$ (right panel) primary beams. The solid curve represents a fit with Eq. (3) and the dotted curve is a Gaussian fit to the right side of the momentum distribution to show the asymmetry of the experimental distributions.

Figure 5

Isotope cross-sections measured in the fragmentation of ${}^{40,48}\mathrm{Ca}$ projectiles on ${}^9\mathrm{Be}$ target (left panel) and in the fragmentation of ${}^{58,64}\mathrm{Ni}$ projectile on ${}^9\mathrm{Be}$ target (right panel).

Figure 6

Measured cross-sections presented as isotope distributions for $5⩽Z⩽20$ elements detected in ${}^{40}\mathrm{Ca}$+${}^9\mathrm{Be}$ reactions at 140 MeV/nucleon. Experimental fragmentation data are shown as filled squares. Filled triangles show the cross-sections of nucleon pickup reactions. EPAX predictions are shown as solid lines. Open squares show ${}^{40}\mathrm{Ca}$+${}^1\mathrm{H}$ at 356 MeV/nucleon.

Figure 7

Measured cross-sections presented as isotope distributions for $5⩽Z⩽20$ elements detected in ${}^{40}\mathrm{Ca}$+${}^{181}\mathrm{Ta}$ reactions at 140 MeV/nucleon. Experimental fragmentation data are shown as filled squares. Filled triangles show the cross-sections of nucleon pickup reactions. EPAX predictions are shown as solid lines.

Figure 8

Measured cross-sections presented as isotope distributions for $5⩽Z⩽20$ elements detected in ${}^{48}\mathrm{Ca}$+${}^9\mathrm{Be}$ reactions at 140 MeV/nucleon. Experimental fragmentation data are shown as filled squares. Filled triangles show the cross-sections of nucleon pickup reactions. EPAX predictions are shown as solid lines. Open squares show ${}^{48}\mathrm{Ca}$+${}^9\mathrm{Be}$ at 212 MeV/nucleon [26]. Open triangles show fragments created in the ${}^{48}\mathrm{Ca}$+${}^2\mathrm{H}$ at 104 MeV/nucleon [27].

Figure 9

Measured cross-sections presented as isotope distributions for $5⩽Z⩽20$ elements detected in ${}^{48}\mathrm{Ca}$+${}^{181}\mathrm{Ta}$ reactions at 140 MeV/nucleon. Experimental fragmentation data are shown as filled squares. Filled triangles show the cross-sections of nucleon pickup reactions. EPAX predictions are shown as solid lines.

Figure 10

Measured cross-sections presented as isotope distributions for $5⩽Z⩽28$ elements detected in ${}^{58}\mathrm{Ni}$+${}^9\mathrm{Be}$ reactions at 140 MeV/nucleon. Experimental fragmentation data are shown as filled squares. Filled triangles show the cross-sections of nucleon pickup reactions. EPAX predictions are shown as solid lines. Open squares show ${}^{58}\mathrm{Ni}$+${}^9\mathrm{Be}$ at 650 MeV/nucleon [28].

Figure 11

Measured cross-sections presented as isotope distributions for $5⩽Z⩽28$ elements detected in ${}^{58}\mathrm{Ni}$+${}^{181}\mathrm{Ta}$ reactions at 140 MeV/nucleon. Experimental fragmentation data are shown as filled squares. Filled triangles show the cross-sections of nucleon pickup reactions. EPAX predictions are shown as solid lines.

Figure 12

Measured cross-sections presented as isotope distributions for $5⩽Z⩽28$ elements detected in ${}^{64}\mathrm{Ni}$+${}^9\mathrm{Be}$ reactions at 140 MeV/nucleon. Experimental fragmentation data are shown as filled squares. Filled triangles show the cross-sections of nucleon pickup reactions. EPAX predictions are shown as solid lines.

Figure 13

Measured cross-sections presented as isotope distributions for $5⩽Z⩽28$ elements detected in ${}^{64}\mathrm{Ni}$+${}^{181}\mathrm{Ta}$ reactions at 140 MeV/nucleon. Experimental fragmentation data are shown as filled squares. EPAX predictions are shown as solid lines.

Figure 14

Ratios of measured fragment cross-sections and predicted cross-sections from EPAX parametrization for ${}^{40,48}\mathrm{Ca}$ projectiles on ${}^9\mathrm{Be}$ target (left panel) and ${}^{58,64}\mathrm{Ni}$ projectiles on ${}^9\mathrm{Be}$ target (right panel). The lightest grey color represents ratios with values greater than 1.